spawn and sync for threads?

[Darren Cruse]

I know that spawn and sync have been provided in the Rhino shell, but not
directly built into the Rhino javascript "language proper" (so to speak).

Will nashorn likewise support spawn and sync in some fashion?

Is the answer - like with Rhino - that it doesn't have to take a stance
it's more for add ons to use java's threading from nashorn as they choose?